textproduct: Rapid City

KEY MESSAGES

-Mild and mainly dry through Thursday

-Critical fire weather conditions for parts of the area through Monday, mainly along and south of I90

-Much colder and unsettled for the end of the week with rain and snow possible by Friday for parts of the area

UPDATE

Issued at 1022 PM MDT Sun Apr 12 2026

Scattered showers have developed across the area this evening, most of them have remained fairly weak, producing only light precip and breezy to gusty winds. One or two stronger cells in northwest SD and southeastern MT are producing lightning strikes. This activity should move out of the region through the overnight hours.

Forecast remains on track with critical fire weather conditions expected to develop across much of western SD into portions of northeastern WY tomorrow as temperatures climb into the 70s to 80s, RHs drop into the teens, and westerly winds pick up ahead of upper level trof. CAMs are showing scattered precip developing over northwestern SD tomorrow afternoon as impulse moves across northern SD/southern ND. While buoyancy is marginal (500-1250 J/kg CAPE per NAM), 0-6 km bulk shear values of 40-60kt could support some stronger cells with small hail however, not expecting any severe weather.

DISCUSSION

(This Afternoon Through Saturday) Issued at 1126 AM MDT Sun Apr 12 2026

Central Rockies upper trough will continue to shift east with another stronger trough dropping into the Pac NW. This will support warm and mainly dry weather through most of Thur. Dry SW flow is ongoing across the southern half of the FA behind a departing impulse. A weak impulse will shift northeast across the region tonight, supporting isolated showers across the far NW. Limited moisture with the bulk of forcing remaining to the NW will highly limited coverage. Flow will increase Monday ahead of the main Rockies upper trough, supporting very dry breezy weather, particularly across the southern half of the FA where critical fire weather conds will occur. The Rockies trough will split with the northern portion possibly supporting a few showers across the far NW Monday afternoon/evening. However, most places will remain dry. Cool front starts to progress east into the area Monday night. The southern portion of the trough will shift east Tues, barely skirting the southeast third of the FA, with maybe a shower or two in south central SD. Cut pops Tue and Wed in line with model trends. Mild weather will continue through Thur as WAA ensues ahead of the next upper trough Wed, which will advect SE in westerly flow out of the Pac NW. This system will force a strong cold front into the region Thur, with strong CAA and wind expected. However, there is growing indications that this trough will split, with limited precip amounts outside of perhaps northeast WY and maybe NW SD, effectively leaving much of western SD with little to no precip. Things quickly then warm back up early next week as the next trough drops into the western CONUS.

AVIATION

(For the 12Z TAFS Through 12Z Tuesday Morning) Issued At 523 AM MDT Mon Apr 13 2026

Mainly VFR conditions are expected from the Black Hills west, and across southern SD for much of the TAF period. Some fog and low ceilings (IFR to LIFR) have advected into northwestern SD, and will persist through the morning hours. This afternoon, thunderstorms will be possible across northeast WY into northwest SD, moving east of the area by 02Z. Hail and strong winds are possible with the heaviest precipitation.

FIRE WEATHER

Issued At 1126 AM MDT Sun Apr 12 2026

Gusty southwest winds, extremely dry air, and lack of appreciable green up will support critical fire weather conditions through Monday over portions of northeast WY and western SD, mainly along and south of I90. A red flag warning remains in effect and has been extended through Monday. The most critical areas will be south of I90 in western SD Monday where RH will drop to 10 percent with winds gusting to around 45 mph in the afternoon. A cool front will drop into the area Monday night with winds diminishing and RH's recovering. Mild on Tue and Wed as an upper level trough skirts south of the area. A strong cold front will move into the region Thur, with chances for rain and snow Friday.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 9 PM MDT /10 PM CDT/ this evening for SDZ320>322-324>326-329-331>335. WY...Red Flag Warning until 9 PM MDT this evening for WYZ315-317.